1. Technical Field of the Invention
The invention relates to a packaging machine equipped with sensors, actuators and drive systems, comprising a servo motor, a central control unit and a system for data transmission, the actual values of the sensors, actuators and drive systems being recorded in digital form in each case and transferred with the use of a transmission protocol via the data transmission system to the central control unit, evaluated by the latter and the determined setpoint values or control commands being also transmitted in digital form and with the use of the transmission protocol from the control system via the data transmission system to the actuators or drives.
2. Description of the Prior Art
In the packaging of foods, a large number of processes are usually necessary, such as feeding the packaging material or container, filling the container, closing the container and labelling the packaged goods. Each of these processes is in turn subdivided into a large number of individual steps, which are executed by different machines or machine components, all the individual steps having to take place synchronously with one another.
Whereas packaging machines with intermeshed mechanical components were formerly used to solve the problem, packaging machines of the current prior art have a large number of “intelligent” sensors, actuators and drives. These elements perform the intended tasks largely “autonomously”, the actuation and coordination of these elements taking place by means of a central control unit. In such cases, there is extensive, usually bidirectional, data exchange between the central control unit and aforementioned elements.
The transmission of the data in the case of packaging machines of the prior art takes place by means of wires via a data transmission system. The wiring provides comparatively high security against transmission errors, since modern packaging machines have a very large number of sensors, actuators and drives, however wiring these elements is associated with high consumption of time and materials, the material including not only the cable but also large distributor cabinets and switch cabinets. Furthermore, the large number of cables often leads to a confusion of cables, which proves disadvantageous when looking for faults.
For transmitting the data and information between the control unit and sensors, actuators and drives, and vice versa, communication protocols are necessary, which regulate the data exchange procedure. With the application of data transmission to the field of packaging machines, these protocols must ensure rapid and reliable data transmission. In particular, with the actuation of drives, it is necessary for the protocol to make the actual and setpoint data available without error and within very short times and with a high time accuracy. The throughput of the data transmission system must be all the greater the higher the degree of automation of the packaging machine and consequently the greater the number of elements that are integrated into the data exchange.